Flywheel for a motor vehicle's drivetrain

Abstract

The present invention relates to a flywheel (1) for a drive train (2) of a motor vehicle (3), with a rotation axis (5) extending along an axial direction (4) and arranged coaxially thereto with a main flywheel mass (7) forming an input side (6), a torque limiting device (8) arranged downstream of the main flywheel mass (7) in a torque transmission path extending from the input side (6), and a torsional vibration damper (9) arranged downstream of the torque limiting device (8) in the torque transmission path; wherein the main flywheel mass (7) has a first stop surface (12) arranged in a radial direction (10) outside the torque limiting device (8) and the torsional vibration damper (9) and extending circumferentially (11);wherein a plurality of mass segments (13) are arranged on the main flywheel (7), immediately adjacent to the first stop surface (12) and distributed along the circumferential direction (11), which in operation of the flywheel (1) are supported on the first stop surface (12) against the radial direction (10).

Description

[0001] The present invention relates to a flywheel with an integrated torque limiting device and an integrated torsional vibration damper.

[0002] In known drive trains, it is required that, in particular, electrical components of the drive system be protected against torque overshoot and sudden torque changes. Such torque overshoots and / or sudden torque changes occur especially when a motor vehicle equipped with the drive train is driving, for example, on an uneven surface, where individual wheels of the motor vehicle occasionally lose their frictional contact with the surface, spin, or are subjected to strong acceleration.

[0003] Common flywheels in drive trains are combined with a torque limiting device to protect against excessive torque. Furthermore, torque transmission systems often include torsional vibration dampers to protect connected components from torsional vibrations, such as those generated during the operation of connected internal combustion engines.

[0004] Friction-based torque limiting devices are well-known. In these designs, friction pairs consisting of organic linings are typically pressed against steel counter-friction discs. The required contact force is typically generated via (disc) springs. These are essentially self-actuated / torque-actuated friction clutches.

[0005] Such torque limiting devices can be designed as a slip clutch.

[0006] A flywheel is known, for example, from DE 10 2020 115 435 A1. In this design, the main rotating mass of the flywheel is manufactured as a single-piece sheet metal forming part. An annular counter plate serves to increase the mass of inertia on the damper inlet side.

[0007] A closed ring (the counter plate) can adequately absorb the centrifugal force occurring during the operation of the flywheel, but is expensive to manufacture.

[0008] Another type of flywheel is known, for example, from DE 10 2022 133 434 A1. In this case, a mass ring arranged on the output side of the flywheel is designed in multiple parts.

[0009] In a multi-part mass ring, the connections of the individual segments, usually rivet connections, are subjected to high stress due to centrifugal force, so that the application is limited (e.g. in terms of mass, diameter, rotational speed).

[0010] Based on this, the present invention aims to propose a flywheel that is both cost-effective to manufacture and has a wide range of applications.

[0011] This problem is solved with a flywheel according to the features of claim 1. Further advantageous embodiments of the invention are specified in the dependent claims. The features listed individually in the dependent claims can be combined with one another in a technologically meaningful manner and can define further embodiments of the invention. In addition, the features specified in the claims are further specified and explained in the description, whereby further preferred embodiments of the invention are presented.

[0012] A flywheel for a motor vehicle drivetrain is proposed. The flywheel comprises • an axis of rotation extending along an axial direction and arranged coaxially to it • a main flywheel forming an input side, • a torque limiting device arranged downstream of the main flywheel in a torque transmission path originating from the input side, and • a torsional vibration damper located downstream of the torque limiting device in the torque transmission path.

[0013] The main flywheel has a first stop surface arranged radially outside the torque limiting device and the torsional vibration damper, and extending circumferentially. A plurality of mass segments are arranged on the main flywheel immediately adjacent to the first stop surface and distributed along its circumference. During operation of the flywheel, the majority of these mass segments bear against the first stop surface in the radial direction.

[0014] In particular, the main flywheel mass forms an input side of the flywheel. The main flywheel mass can have several mounting holes distributed around its circumference, allowing it to be bolted to, for example, a crankshaft of an internal combustion engine.

[0015] A torque limiting device, particularly a slip clutch, is arranged downstream of the main flywheel in a torque transmission path originating from the input side. A torsional vibration damper is arranged downstream of the torque limiting device in the torque transmission path. The torsional vibration damper has, in particular, an output flange and a hub forming an output side, the hub being rotationally fixed to the output flange. A transmission input shaft, for example, can be connected to the flywheel via the hub.

[0016] In particular, a plurality of mass segments are arranged on the main flywheel immediately adjacent to the first stop surface and distributed along the circumferential direction. The mass segments are of identical construction. The individual mass segments are arranged adjacent to each other along the circumferential direction. At least two, preferably at least four, or at least six or eight mass segments are provided. In particular, a maximum of 20 mass segments are provided.

[0017] In particular, during operation of the flywheel (i.e., during intended use of the flywheel, e.g., in a motor vehicle), each mass segment is supported against the first contact surface in the radial direction. As a result of this first contact surface, any fastening elements provided or present for attaching the mass elements to the main flywheel mass are subjected to a lower or limited force.

[0018] Designing the mass segments as multiple individual parts and supporting them via a first contact surface of the main flywheel enables both a cost-effective flywheel design and a wide range of applications. This reliably prevents overloading of the fastening elements.

[0019] In particular, the main flywheel is a single piece formed from a sheet metal component, with the contact surface created by folding the sheet metal component. Especially with such sheet metal parts, the material thickness is limited due to the necessary forming or stamping techniques, so that additional mass segments are (or must be) used to achieve the required moment of inertia.

[0020] In particular, the first contact surface is formed by a deformed or bent section of the sheet metal component. Specifically, at least one mass segment is movably arranged on the main flywheel in the radial direction. This allows the mass segment to be attached to the main flywheel during assembly, and then, during operation of the flywheel, to contact the first contact surface due to the centrifugal force generated.

[0021] In particular, the mass segment (after proper assembly or attachment to the main flywheel) is movable only in the radial direction. Specifically, the mass segment is fixed to the main flywheel with respect to the axial and / or circumferential directions. Fixed means, in particular, that any movement (a path of movement, especially in a specific direction) is only possible in the single-digit or double-digit micrometer range, but in any case less than 0.4 millimeters or even less than 0.2 millimeters. Movable, on the other hand, means, in particular, that the mass segment is movable by at least 0.4 millimeters or at least one millimeter. Specifically, the movement, e.g., with respect to the radial direction, is limited to a maximum of 5 millimeters.

[0022] In particular, at least one mass segment is attached to the main flywheel via a fastening element, wherein the mass segment is pivotable about the fastening element and about a pivot axis parallel to the axial direction. In particular, the fastening element is arranged eccentrically relative to the mass segment, such that the distances extending along the circumferential direction between the fastening element and the respective ends of the mass segments are different. In particular, the movement along the radial direction is then achieved by pivoting the mass segment about the fastening element.

[0023] The fastening element can extend through the mass segment or be arranged between two adjacent mass segments.

[0024] One or more fastening elements can be provided per mass segment.

[0025] In particular, at least one mass segment is attached to the main flywheel and elastically prestressed in the axial direction. Specifically, the fastening element and / or the mass segment can be elastically deformable, so that a prestress is generated via the elastic deformation of the fastening element or the mass segment.

[0026] In particular, at least one mass segment has a second stop surface against which a disc spring of the slip clutch is supported in the circumferential direction during operation of the flywheel. The disc spring is arranged, in particular, in the radial direction between the axis of rotation and the mass segment. In particular, the mass segment can have a contour forming the second stop surface, such that the disc spring is supported against it in the circumferential direction.

[0027] In particular, the movement or path of movement of at least one mass segment is limited by stops in all directions (axial direction, radial direction, circumferential direction), wherein a maximum (or maximum possible) path of movement in the radial direction is at least 50% greater than a maximum (or maximum possible) path of movement in any other direction.

[0028] The fastening element can be designed as a bolt, a screw, or a rivet. In particular, at least one mass segment is attached to the main flywheel by at least one fastening element designed as a rivet.

[0029] In particular, the rivet is a cylindrically shaped bolt with a contact geometry that is rotationally symmetrical (at least) in the area of ​​the connection between the main flywheel and the mass element.

[0030] In particular, the rivet is a flat rivet with a contact geometry that is at most axially symmetrical, at least in the area of ​​the connection between the main flywheel and the mass element.

[0031] The descriptions of the flywheel components (e.g., the mass segments or the fastening elements, etc.) apply in particular to one of the majority of these components, to a specific number of the majority, or to all of the components described.

[0032] The use of indefinite articles (“a”, “an”, “one”, and “ones”), particularly in the claims and the description reproducing them, is to be understood as such and not as a numeral. Accordingly, terms or components introduced by these articles are to be understood as appearing at least once and, in particular, as potentially appearing multiple times.

[0033] It should be noted as a precaution that the numerical terms used here ("first", "second", etc.) primarily serve (only) to distinguish between several similar objects, quantities, or processes, and thus do not necessarily dictate any dependency and / or sequence between these objects, quantities, or processes. Should a dependency and / or sequence be required, this is explicitly stated here, or it will be obvious to a person skilled in the art upon studying the specific configuration described. Where a component can occur multiple times ("at least one"), the description of one of these components may apply equally to all or some of the multiple components, but this is not mandatory.

[0034] The invention and its technical context are explained in more detail below with reference to the accompanying figures. It should be noted that the invention is not limited by the exemplary embodiments shown. In particular, it should be noted that the figures, and especially the depicted dimensions, are only schematic. They show: Fig. 1: A drive train of a motor vehicle with a known flywheel in perspective view; Fig. 2: A first design variant of a flywheel in perspective view; Fig. 3: the flywheel after Fig. 2 in a top view; Fig. 4: a detail of the flywheel after Fig. 2 and Fig. 3 in a perspective view in section; Fig. 5: a detail of the flywheel after Fig. 2 and Fig. 3 in a top view; Fig. 6: a mass segment of the flywheel after Fig. 2, Fig. 3, Fig. 4 to Fig. 5 in a perspective view; Fig. 7: a fastening element of the flywheel according to Fig. 2, Fig. 3, Fig. 4 to Fig. 5; Fig. 8: a second design variant of a flywheel in perspective view; Fig. 9: a detail of the flywheel after Fig. 8 in a perspective view in section; Fig. 10: a detail of the flywheel after Fig. 8 and Fig. 9 in a top view; Fig. 11: a mass segment of the flywheel after Fig. 8, Fig. 9 to Fig. 10 in a perspective view; and Fig. 12: a fastening element of the flywheel according to Fig. 8, Fig. 9 to Fig. 10.

[0035] Fig. Figure 1 shows a drive train 2 of a motor vehicle 3 (both only indicated) with a known flywheel 1 in perspective view.

[0036] The flywheel 1 comprises a rotation axis 5 extending along an axial direction 4 and, arranged coaxially thereto, a main flywheel mass 7 forming an input side 6, a torque limiting device 8 which is arranged downstream of the main flywheel mass 7 in a torque transmission path emanating from the input side 6, and a torsional vibration damper 9 which is arranged downstream of the torque limiting device 8 in the torque transmission path.

[0037] The main flywheel 7 has a first stop surface 12 arranged in a radial direction 10 outside the torque limiting device 8 and the torsional vibration damper 9 and extending circumferentially 11.

[0038] The main flywheel 7 has several screw holes 22 distributed in the circumferential direction 11 of the flywheel 1, via which the main flywheel 7 can be screwed to, for example, a crankshaft of an internal combustion engine of the motor vehicle 3.

[0039] The torque limiting device 8, designed as a slip clutch and comprising a disc spring 18, is arranged downstream of the main flywheel 7 in a torque transmission path originating from the input side 6. The slip clutch includes at least two surfaces in frictional contact, which are pre-tensioned against each other in the axial direction 4 by the disc spring 18, such that below a set limit torque the two surfaces rotate together in a rotationally fixed manner and rotate against each other above the limit torque until the applied torque has dropped below the limit torque again.

[0040] The torsional vibration damper 9 is arranged downstream of the torque limiting device 8 in the torque transmission path. The torsional vibration damper 9 has an output flange 23 and a hub 24 forming an output side, the hub 24 being non-rotatably connected to the output flange 23. A transmission input shaft can be connected to the flywheel 1, for example, via the hub 24.

[0041] Fig. Figure 2 shows a first design variant of a flywheel 1 in perspective view. Fig. 3 shows the flywheel 1 after Fig. 2 in a top view. Fig. Figure 4 shows a detail of flywheel 1. Fig. 2 and Fig. 3 in a perspective view in section. Fig. Figure 5 shows a detail of flywheel 1. Fig. 2 and Fig. 3 in a top view. Fig. Figure 6 shows a mass segment 13 of the flywheel 1 after Fig. 2, Fig. 3, Fig. 4 to Fig. 5 in a perspective view. Fig. Figure 7 shows a fastening element 15 of the flywheel 1. Fig. 2, Fig. 3, Fig. 4 to Fig. 5. The Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. Seven will be described together below. The explanations regarding the Fig. 1 is referred to.

[0042] The flywheel 1 comprises a rotation axis 5 extending along an axial direction 4 and, arranged coaxially thereto, a main flywheel mass 7 forming an input side 6, a torque limiting device 8 which is arranged downstream of the main flywheel mass 7 in a torque transmission path emanating from the input side 6, and a torsional vibration damper 9 which is arranged downstream of the torque limiting device 8 in the torque transmission path.

[0043] The main flywheel 7 has a first stop surface 12 arranged in a radial direction 10 outside the torque limiting device 8 and the torsional vibration damper 9 and extending circumferentially 11.

[0044] A plurality of mass segments 13 are arranged on the main flywheel 7, immediately adjacent to the first stop surface 12 and distributed along the circumferential direction 11. During operation of the flywheel 1, the plurality of mass segments 13 bear against the first stop surface 12 in the radial direction 10.

[0045] Each mass segment 13 is supported against the first stop surface 12 in the radial direction 10 during operation of the flywheel 1 (i.e., during intended use of the flywheel 1, e.g., in a motor vehicle 3). As a result of the first stop surface 12, fastening elements 15, here rivets, which are provided or present for fastening the mass elements 13 to the main flywheel 7, are subjected to a lower or limited force.

[0046] The design of the mass segments 13 as a plurality of individual parts and their support via a first stop surface 12 of the main flywheel 7 enables, on the one hand, a cost-effective design of the flywheel 1 and, on the other hand, a wide range of applications. Overloading of the fastening elements 15 can thus be reliably prevented.

[0047] The main flywheel 7 is a single piece and designed as a formed sheet metal component, with the first contact surface 12 being formed by a fold 14 of the sheet metal component. Especially with such sheet metal parts, the material thickness is limited due to the necessary forming or stamping technique, so that additional mass segments 13 are (or must be) used to achieve the required moment of inertia.

[0048] The first stop surface 12 is formed by a deformed or bent area of ​​the sheet metal component.

[0049] The mass segments 13 are movably arranged on the main flywheel 7 in the radial direction 10. This allows each mass segment 13 to be attached to the main flywheel 7 during assembly and then, during operation of the flywheel 1, to bear against the first stop surface 12 due to the centrifugal force. For this purpose, guides 25 are provided at the bore in the mass segment 13, along which the mass segment 13 can be moved along the radial direction 10 on the stationary fastening element 15 (see Fig. 6).

[0050] The mass segment 13 (after proper assembly or attachment to the main flywheel 7) is movable only in the radial direction 10. The mass segment 13 is fixed to the main flywheel 7 with respect to the axial direction 4 and the circumferential direction 11.

[0051] The mass segments 13 are each attached to the main flywheel 7 by means of a fastening element 15, wherein the mass segment 13 is pivotable about the fastening element 15 and about a pivot axis 16 parallel to the axial direction 4. In the first embodiment, the fastening element 15 is arranged exactly centrally opposite the mass segment 13, so that the distance 26 extending along the circumferential direction 11 between the fastening element 15 and the respective end 27 of the respective mass segment 13 is always the same.

[0052] The mass segments 13 are attached to the main flywheel 7 and are elastically pre-tensioned with respect to the axial direction 4. The fastening element 15, here the rivet (according to Fig. 7) with the recess 28 (at the rivet head), is elastically deformable, so that a preload is generated via the elastic deformation of the fastening element 15.

[0053] The mass segments 13 have a second stop surface 17 against which a disc spring 18 of the slip clutch is supported during operation of the flywheel 1 relative to the circumferential direction 11. The disc spring 18 is arranged in the radial direction 10 between the axis of rotation 5 and the mass segments 13. The mass segments 13 have a contour forming the second stop surface 17, so that the disc spring 18 is supported against it relative to the circumferential direction 11.

[0054] A movement or path of movement 29 of the mass segments 13 relative to all directions (axial direction 4, radial direction 10, circumferential direction 11) is limited by stops, wherein a maximum (or maximum possible) path of movement 19 (i.e., between the stops) in the radial direction 10 is several times greater than a maximum (or maximum possible) path of movement 19 (between the respective stops) in any other direction 4, 11. In the first embodiment, the stops are formed by other mass segments 13, the first stop surface 12, the fastening element 15, the disc spring 18, and by the flat rivets used to fasten the disc spring 18 (see Fig. 2, Fig. 3, Fig. 4 to Fig. 5) realized.

[0055] The mass segments 13 are each attached to the main flywheel 7 by a fastening element 15 designed as a rivet.

[0056] The rivet is a cylindrically shaped bolt with a contact geometry 21 that is rotationally symmetrical (at least) in the area of ​​the connection 20 between main flywheel 7 and mass element 13.

[0057] Fig. Figure 8 shows a second design variant of a flywheel 1 in perspective view. Fig. Figure 9 shows a detail of flywheel 1. Fig. 8 in a perspective view in section. Fig. Figure 10 shows a detail of flywheel 1. Fig. 8 and Fig. 9 in a top view. Fig. Figure 11 shows a mass segment 13 of the flywheel 1 after Fig. 8, Fig. 9 to Fig. 10 in a perspective view. Fig. Figure 12 shows a fastening element 15 of the flywheel 1. Fig. 8, Fig. 9 to Fig. 10. The Fig. 8, Fig. 9, Fig. 10, Fig. 11 to Fig. The 12 are described together below. The explanations regarding... Fig. 1, Fig. 2, Fig. 3, Fig. 4, Fig. 5, Fig. 6 to Fig. 7 is referred to.

[0058] In contrast to the first embodiment, the rivet used as a fastening element for the mass segments 13 is a flat rivet with a contact geometry 21 that is only axially symmetrical, at least in the area of ​​the connection 20 between the main flywheel 7 and the mass element 13. The flat rivet is in the head area (in Fig. 12 above) is elastically designed relative to the axial direction 4. The two feet (in Fig. 12 below) of the flat rivet are elastically deformable with respect to the circumferential direction 11 and cause the positive locking with respect to the axial direction 4, together with the head area. Reference symbol list 1 flywheel 2 Powertrain 3 Motor vehicle 4 axial direction 5 axis of rotation 6 Entrance page 7 Main flywheel 8 Torque limiting device 9 torsional vibration dampers 10 radial direction 11 Circumferential direction 12 first stop surface 13 Mass segment 14 folds 15 Fastening element 16 swivel axes 17 second stop surface 18 Belleville washers 19 maximum range of motion 20 connection 21 Contact geometry 22 screw holes 23 Output flange 24 hub 25 Leadership 26 distance 27 End 28 recess 29 Movement path QUOTES INCLUDED IN THE DESCRIPTION

[0000] This list of documents cited by the applicant was automatically generated and is included solely for the reader's convenience. The list is not part of the German patent or utility model application. The DPMA accepts no liability for any errors or omissions. Cited patent literature

[0000] DE 10 2020 115 435 A1

[0006] DE 10 2022 133 434 A1

[0008]

Claims

Flywheel (1) for a drive train (2) of a motor vehicle (3), with an axis of rotation (5) extending along an axial direction (4) and arranged coaxially thereto with a main flywheel mass (7) forming an input side (6), a torque limiting device (8) arranged downstream of the main flywheel mass (7) in a torque transmission path extending from the input side (6), and a torsional vibration damper (9) arranged downstream of the torque limiting device (8) in the torque transmission path; wherein the main flywheel mass (7) has a first stop surface (12) arranged in a radial direction (10) outside the torque limiting device (8) and the torsional vibration damper (9) and extending circumferentially in a circumferential direction (11);wherein a plurality of mass segments (13) are arranged on the main flywheel (7), immediately adjacent to the first stop surface (12) and distributed along the circumferential direction (11), which in operation of the flywheel (1) are supported on the first stop surface (12) against the radial direction (10). Flywheel (1) according to claim 1, wherein the main flywheel mass (7) is formed in one piece as a formed sheet metal component, wherein the first stop surface (12) is formed by a fold (14) of the sheet metal component. Flywheel (1) according to one of the preceding claims, wherein at least one mass segment (13) is movably arranged on the main flywheel (7) in the radial direction (10). Flywheel (1) according to one of the preceding claims, wherein at least one mass segment (13) is attached to the main flywheel (7) via a fastening element (15), wherein the mass segment (13) is pivotable about the fastening element (15) and about a pivot axis (16) parallel to the axial direction (4). Flywheel (1) according to one of the preceding claims, wherein at least one mass segment (13) is attached to the main flywheel (7) and is elastically prestressed relative to the axial direction (4). Flywheel (1) according to one of the preceding claims, wherein at least one mass segment (13) has a second stop surface (17) on which a disc spring (18) of the torque limiting device (8) is supported in the operation of the flywheel (1) against the circumferential direction (11). Flywheel (1) according to one of the preceding claims, wherein a movement of at least one mass segment (13) relative to all directions (4, 10, 11) is limited by stops, wherein a maximum movement path (19) in the radial direction (10) is at least 50% greater than the maximum movement path (19) in any other direction (4, 11). Flywheel (1) according to one of the preceding claims, wherein at least one mass segment (13) is attached to the main flywheel mass (7) by at least one fastening element (15) designed as a rivet. Flywheel (1) according to claim 8, wherein the rivet is a cylindrically shaped bolt with a contact geometry (21) that is rotationally symmetrical at least in the area of ​​the connection (20) between main flywheel (7) and mass element (13). Flywheel (1) according to claim 8, wherein the rivet is a flat rivet with a contact geometry (21) that is at most axially symmetric in the area of ​​the connection (20) between main flywheel (7) and mass element (13).

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